In these studies, we will define the patterns and natural history of insulin secretion in kidney-pancreas transplant recipients. The transplanted pancreas is a unique human model in which to study beta cell function since the pancreas is situated in an abnormal anatomic site, drains into the systemic rather than the portal circulation, and has been severed from it central neurological connections. The proposed studies will define the quantitative and qualitative alterations in insulin secretion which occur in these patients.